s = "hello world";
i,j = string.find(s,"hello")
print(i,j)
print(string.sub(s,i,j))
print(string.find(s,"world"))
i,j = string.find(s,"l")
print(i,j)
print(string.find(s,"lll"))
-- 第四个参数为是否进行简单搜索
-- 所谓简单搜索就是忽略模式而在目标字符串中进行单纯的“查找子字符串”的动作
print(string.find("a [word]","[",1,true))
